diff --git a/4-03/homework_4_3_routers_config.txt b/4-03/homework_4_3_routers_config.txt
index d29fbf3..76b082d 100644
--- a/4-03/homework_4_3_routers_config.txt
+++ b/4-03/homework_4_3_routers_config.txt
@@ -34,9 +34,9 @@ R4:
 	R4(config)#interface Gi0/0
 	R4(config-if)#ip address 172.16.1.4 255.255.255.0
 	R4(config)#interface Gi0/1
-	R4(config-if)#ip address 192.168.34.4 255.2555.255.0
+	R4(config-if)#ip address 192.168.34.4 255.255.255.0
 	R4(config)#interface Gi0/2
-	R4(config-if)#ip address 192.168.24.4 255.2555.255.0
+	R4(config-if)#ip address 192.168.24.4 255.255.255.0
 	R4(config)#router ospf 1
 	R4(config-router)#network 4.4.4.4 0.0.0.0 area 3
 	R4(config-router)#network 172.16.1.0 0.0.0.255 area 3
@@ -47,16 +47,16 @@ R5:
 	R5(config)#interface Gi0/0
 	R5(config-if)#ip address 172.16.1.5 255.255.255.0
 	R5(config)#interface Gi0/1
-	R5(config-if)#ip address 192.168.15.5 255.2555.255.0
+	R5(config-if)#ip address 192.168.15.5 255.255.255.0
 	R5(config)#router ospf 1
 	R5(config-router)#network 172.16.1.0 0.0.0.255 area 0
 	R5(config-router)#network 192.168.15.0 0.0.0.255 area 0
 
 R6:
 	R6(config)#interface Gi0/0
-	R6(config-if)#ip address 192.168.67.6 255.2555.255.0
+	R6(config-if)#ip address 192.168.67.6 255.255.255.0
 	R6(config)#interface Gi0/2
-	R6(config-if)#ip address 192.168.36.6 255.2555.255.0
+	R6(config-if)#ip address 192.168.36.6 255.255.255.0
 	R6(config)#router ospf 1
 	R6(config-router)#network 192.168.36.0 0.0.0.255 area 7
 	R6(config-router)#network 192.168.67.0 0.0.0.255 area 7
@@ -65,7 +65,7 @@ R7:
 	R7(config)#interface Loopback 7
 	R7(config-if)#ip address 7.7.7.7 255.255.255.255
 	R7(config)#interface Gi0/0
-	R7(config-if)#ip address 192.168.67.7 255.2555.255.0
+	R7(config-if)#ip address 192.168.67.7 255.255.255.0
 	R7(config)#router ospf 1
 	R7(config-router)#network 7.7.7.7 0.0.0.0 area 7
 	R7(config-router)#network 192.168.67.0 0.0.0.255 area 7